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If the 10th term of an AP is 31 and first term is 4, common difference is
A3
B2
C4
D5
Answer & Solution
Correct answer: A. 3
1. Use a_10 = a + 9 d.
2. 31 = 4 + 9 d.
3. 9 d = 27, so d = 3.
4. Hence d = 3.
_Source: Selina Concise Mathematics Class 10, Ch on Arithmetic Progression (Mistral OCR'd PDF), section on common difference_
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